Attention deficit hyperactivity disorder (ADHD) is the subject of considerable controversy. Many observers decry the now-routine use of stimulant drugs like Ritalin to control symptoms. Meanwhile, others say that ADHD diagnoses represent the "medicalization" of behaviors that fall at one end of the normal scale ... which may be signs of an unusally creative, intelligent mind.
Claims that ADHD is an imaginary disease were undermined by a recent UC Davis study showing that two brain areas failed to connect when children with ADHD attempted a task that measures attention (Mazaheri A et al. 2010).
Now, a new study from Australia lends support to the idea that nutritionally inferior diets may play a role in elicting the disorder. The term “standard American diet” is used by nutrition researchers to describe the most common eating pattern in this country. And that semi-official appellation yields an acronym – SAD – that’s all too fitting in light of the clearly adverse health impacts of the nation’s dominant eating pattern.
The standard American diet is high in sugars, refined starches (white flour products), pro-inflammatory omega-6 fats, saturated fats, and sodium … but low in fruits and vegetables, whole grains, and fish. As it happens, the standard Australian diet closely resembles the standard American diet, and has equally adverse health effects. So Americans should be concerned by new research that links the standard Australian diet to increased risk of attention deficit hyperactivity disorder (ADHD) among adolescents.
The new findings suggests that risk of ADHD in Australian adolescents could be linked to Western diets, which tend to be high in total fat, saturated fat, refined sugar, and sodium.
Before we examine the Aussie study, let’s quickly review the evidence concerning diet and food additives as an ADHD risk factor.
ADHD risk factors: A look at the evidence
Some studies have found links between food additives and ADHD, but the evidence is mixed and points to greater susceptibility in some children than others.
Evidence of a link between sugar alone and higher ADHD risk or transitory behavior problems is considerably weaker.
On the prevention side, some research suggests a potential role for omega-3 fatty acids in reducing the risks of ADHD and improving behavior and learning among children with ADHD. And last year, a Spanish scientific team that reviewed all of the available evidence noted the factors most closely linked to ADHD risk or prevention, including a possible role of the omega-3/omega-6 fat intake imbalance characteristic of Western diets. “[ADHD] has been related to many factors such as diet, additives, toxic substances from the environment, low protein diets with a high carbohydrate content, unbalanced minerals intake, deficits in intake of essential fatty acids, phospholipids, and amino acids, thyroid disorders, and vitamin B complex disorders ...One of the changes that we want to emphasize is related to the omega-6-rich vegetable oils that dominate human consumption and the reduction in fatty acids from the omega-3 family. The effect of an omega-3 intake deficit is even worse when the amount of dietary omega-6 fat increases ...”
Eaten in excess, omega-6 fatty acids tend to promote inflammation and are associated with higher risk of depression and cancer, while omega-3s tend to have opposite effects.
Omega-6 fats compete with dietary omega-3s for absorption, and omega-6s abound in processed and prepared foods and the cheap vegetable oils most commonly used in them and in American kitchens (corn, soy, safflower, cottonseed, and sunflower).
The authors of the new study analyzed the dietary patterns of 1,799 adolescents and classified their diets as “Healthy” or “Western” (Howard AL et al. 2010).
The teens were participants in the Raine Study from Perth, Australia. Researchers have been tracking this group of children since their birth in 1989.
Young teens were defined as eating a “Healthy” diet pattern if they consumed relatively high amounts of fresh fruit and vegetables, whole grains, and fish. This diet pattern also tended to deliver more omega-3 fatty acids, folate (a B vitamin involved in brain health), and fiber.
The “Western” diet pattern was defined as one in which teens tended to eat more takeout foods, sweets, pastries, and processed, fried, or refined foods. This diet pattern delivered less omega-3s but more total fat, saturated fat, omega-6 fats, refined sugar, and sodium.
A team led by child nutrition specialist Wendy Oddy, Ph.D., compared the teens’ diet patterns to their health records, looking for any diagnoses of ADHD by the age of 14 years. Out of the total of 1,799 teens, 115 (91 boys and 24 girls) had been diagnosed with ADHD by age 14.
After adjusting the results to account for various known social and family influences on ADHD risk, the Aussie team found that, compared with kids eating the “Healthy” diet, the kids who ate a “Western” style diet were more than twice as likely to have received an ADHD diagnosis.
When they looked at specific foods, an ADHD diagnosis was associated with diets especially high in takeout foods, processed meats, red meat, high-fat dairy products, sweets, and pastries.
Scientists attribute some of “Healthy” diet’s protection to omega-3s
Professor Oddy attributed some of the risk reduction of the Health diet pattern to fish fats: “We suggest that a Western dietary pattern may indicate the adolescent has a less optimal fatty acid profile, whereas a diet higher in omega-3 fatty acids is thought to hold benefits for mental health and optimal brain function.” (TICHR 2010)
She also proposed that the Western dietary pattern doesn’t provide enough of certain other essential micronutrients needed for optimal attention and concentration.
The Aussies did not deny the possible influence of artificial additives, nor the possibility that kids susceptible to ADHD tend to make bad, impulsive eating choices: “… we cannot be sure whether a poor diet leads to ADHD or whether ADHD leads to poor dietary choices and cravings.” (TICHR 2010)
Needless to say, we need more studies to confirm the link seen in this study, and to pinpoint the food choices most responsible for raising the risk of ADHD.
Sources
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